Artillery would be insufficient. We are talking 20kg of HE per shell at most. And it would be very inefficient to use heavy missiles or bombs, though I suppose if enough were used it may work.
But given that the entire powerplant section and its river channel was also demolished (visible on all the videos), this looks like a comprehensive demolition of the entire facility. There would be no need to do that just to make the primary section of the dam fail. Nor could that be an accident caused by high water.
It was already reported that Russians were controlling the water levels behind the dam, and after keeping it quite low for a while had built it back up to a very high level, to do the most damage. Comment #108 gives a very detailed explanation of how Russia’s explosion ran away from them and caused much more damage than expected. Especially to Russian fortifications and supplies east of Kherson.. In addition, lowering water levels in the upper river will be easier for Ukraine’s troops to cross now by special means.
It does appear to be “demolition” and not artillery despite the clickbait YouTube crap.